Macular degeneration is a medical condition predominantly found in elderly adults in which the center of the inner lining of the eye, known as the macula area of the retina, suffers thinning, atrophy, and in some cases bleeding. This can result in loss of central vision, which entails inability to see fine details, to read, or to recognize faces. According to the American Academy of Ophthalmology, it is the leading cause of central vision loss (blindness) and in the United States for those over the age of fifty years. Although some macular dystrophies that affect younger individuals are sometimes referred to as macular degeneration, the term generally refers to age-related macular degeneration (AMD).
Advanced AMD, which is responsible for profound vision loss, has two forms: dry and wet. Central geographic atrophy, the dry form of advanced AMD, results from atrophy to the retinal pigment epithelial layer below the retina, which causes vision loss through loss of photoreceptors (rods and cones) in the central part of the eye. While no treatment is currently available for this condition, vitamin supplements with high doses of antioxidants, Lutein and Zeaxanthin, have been demonstrated by the National Eye Institute and others to slow the progression of dry macular degeneration and in some patients, improve visual acuity.
Neovascular or exudative AMD, the wet form of advanced AMD, causes vision loss due to abnormal blood vessel growth in the choriocapillaries, through Bruch's membrane, ultimately leading to blood and protein leakage below the macula. Bleeding, leaking, and scarring from these blood vessels eventually cause irreversible damage to the photoreceptors and rapid vision loss if left untreated.
Until recently, no effective treatments were known for wet macular degeneration. However, anti-VEGF (anti-Vascular Endothelial Growth Factor) agents, when injected directly into the vitreous humor of the eye using a small, painless needle, can cause contraction of the abnormal blood vessels and improvement of vision. The injections frequently have to be repeated on a monthly or bi-monthly basis. Examples of these agents include Lucentis, Avastin and Macugen. Only Lucentis and Macugen are FDA approved as of April 2007, and only Lucentis and Avastin appear to be able to improve vision, but the improvements are slight and do not restore full vision. Thus, needed in the art are compositions and methods treat or prevent macular degeneration.
Organ transplant has become an established technique for treatment of various diseases and disorders. However, the decrease in viability of the organ after removal from the donor is a significant limiting factor to the success of organ transplants. Generally, organs are preserved after removal from the donor by hypothermic storage and continuous perfusion. Hypothermic storage generally means rapid cooling of the organ to a temperature between 0° and 4° C., and decreases the rate at which intracellular enzymes degrade. However, injury to the organ occurs through damage to epithelial and endothelial cells, during cold storage and upon reperfusion with a warm reperfusion solution upon transplant into the recipient. Such ischemia reperfusion injury to organs commonly leads to delayed or diminished organ function, and predisposes the organ to rejection. Therefore, there is a need in the art for improved methods of preservation of organs, to extend the viability of the organ and to improve organ function following transplant.